New York City police have arrested four suspects found with more than 350 bags of suspected heroin in an apartment, as they investigate the death of actor Philip Seymour Hoffman.

Police said they arrested three men and one woman Tuesday in a raid on a Manhattan apartment not far from the Greenwich Village apartment where Hoffman's body was found on Sunday.

Also on Tuesday, police said the heroin found at Hoffman's apartment did not contain fentanyl, a powerful additive linked to 22 fatal drug overdoses recently in Pennsylvania.

Writer, director, and cast member Philip Seymour Hoffman arrives at the premiere of "Jack Goes Boating" in Los Angeles on Sept. 13, 2010.

Police said they went to the actor's home Sunday after receiving a call from one of his friends. The Associated Press and TheNew York Times, citing law enforcement officials, said investigators found a syringe in Hoffman's arm and an envelope containing what was believed to be heroin. An autopsy is being conducted.

Hoffman's family is reported to be planning a private funeral and a memorial service, both expected to be held in New York.

Hoffman spoke candidly over the years about past struggles with drug addiction. After 23 years of being sober, he acknowledged in interviews last year that he had relapsed and developed a heroin problem that led to a stint at a rehabilitation facility.